Two contemporary apparatuses have been employed to initiate flashlamp ignition prior to the main energy dump. The first of these employed what is designated as a "simmer method" wherein an external power supply is used to provide a constant current through the flashlamp thereby keeping it on at all times between pulses. In the apparatus of the present invention, the required voltage for initiating current flow through the flashlamp can be tapped off the transformer supplying voltage to the main energy supply whereby no external power source is required. Further, there is no wasted power as in the simmer method, for the flashlamp is only on for a brief time before the main energy dump. This results in improved total power efficiency.
The second contemporary apparatus employs what is designated the "pseudo-simmer method" wherein a silicon controlled rectifier which controls energy flow to the flashlamp is bypassed by a resistor to provide sufficient current to keep the flashlamp on until the silicon controlled rectifier is triggered at which time the resistor is effectively eliminated as an alternate current path. Disadvantages of this apparatus is that the power loss in the resistor is non-recoverable whereby the overall efficiency thereof is reduced compared to that of an apparatus employing the simmer method.